How do solar panels work? We’ve spoken generally about how solar panels harness the power of the sun and allow us to convert its energy into electricity for use in various ways. But, on a technical level solar panels consist of photovoltaic (PV) cells that, when hit with sunlight, absorb energy and cause them to vibrate. That vibration generates solar electricity. This action is known as the Photovoltaic Effect.
Solar Panel Cell Count and efficiency
What we’re discussing in this blog are the three main types of solar panel cells available: polycrystalline, mono-crystalline and thin-film. All of which differ in efficiency. Why do some work more effectively than others? The power output of a PV panel directly relates to the quality and the efficiency of the solar cells…it’s not always about volume.
Mono-crystalline Solar Panels
As the name indicates, Mono-crystalline Solar Panels are made up of single crystal silicon solar cells (mono – crystalline). Considered to be the purest form of solar panel, it’s usually recognisable from its uniform dark colour and rounded edges.
These solar cells are produced by using pure blocks of silicon to form bars which are then cut into wafers. The shape and finish of these bars is round and smooth which allows them to operate to an optimum. These bars are very recognisable, though the production process is seen to be somewhat wasteful and time consuming.
They are considered to be a premium panel and while more expensive than their counterparts, tend to last longer and produce electricity at a higher rate.
Advantages of mono-crystalline panels
- The silicons high purity means these panels have one of the highest efficiency ratings. 15 – 20%
- They take up less space than their counterparts due to the aforementioned high efficiency rating.
- Comparatively, they’re also less affected by weather
Disadvantages of mono-crystalline panels
- Their performance decreases as temperatures increase
- Due to their high efficiency and the quality of the silicon that’s used, they’re more expensive.
Polycrystalline Solar Panels
Polycrystalline panels, also referred to as ‘multi-crystalline’ panels are usually placed in the mid-range bracket in terms of affordability and efficiency. While they are made of silicon, unlike mono-crystalline cells, they are made from many (poly) fragments of silicon crystal. This results in a reduced output and a shorter lifespan. However, that is reflected in cost.
Where it’s an expensive process to create mono-crystalline panels, polycrystalline panels are made by melting raw silicon together and pouring the results into moulds to make bars. They don’t require the same finishing as the mono-crystalline panels. This is less wasteful, less expensive and a much faster process.
The polycrystalline panel is easily identifiable from its blue, speckled appearance. The speckles are caused by the number of crystals in each cell which can be further exaggerated by the sunlight reflecting off them.
Advantages of polycrystalline panels
- Polycrystalline panels still have an impressive efficiency rating of 13 – 17%
- They offer a less expensive alternative due to the melted fragments of silicon
- Polycrystalline panels will generate more electricity over the year due to their high-temperature tolerance.
Disadvantages of polycrystalline panels
- They have a lower efficiency rating compared to mono-crystalline panels
- While more temperature tolerant, they can be sensitive to higher temperatures to a greater extent. This means they’re more likely to have a shorter lifespan
THIN-FILM SOLAR PANELS
Again, the name gives us a little information straight off the bat. Unlike the previous two panel types, thin-film solar panels are thin, with a shallow profile. In fact, the cells within the panels are roughly 350 times thinner than their competitors.
Rather than using pure silicon, these are produced using layers of semi-conducting materials – Amorphous silicon, Cadmium telluride, Copper indium gallium selenide, Organic PV cells within conducting layers placed between them. These layers are topped off with glass, helping to capture sunlight.
More panels and more roof space would be required to produce the same amount of solar energy compared to crystalline panels. They also tend to degrade at a faster rate than the crystalline panels which results in companies giving shorter warranties.
Despite their bad points, their flexibility makes them suitable for a range of applications that crystalline panels are not.
Advantages of thin film panels
- They can be manufactured to be flexible, making them widely applicable to a range of situations and building types
- Mass production is easy to achieve, making them potentially cheaper to produce than crystalline solar cells
- Shading has a similar effect on their efficiency
- They tend to be lighter than crystalline systems
Disadvantages of thin film solar panels
- They are not ideal for domestic use as thy take up a lot of space
- Low space efficiency means that they will cause further expenses in the form of enhancers, like cables of support structures
- They have a shorter lifespan and so shorter warranty periods
SO WHICH TYPE OF SOLAR PANEL IS THE BEST?
Well, from our synopsis of each, there really is a front runner in terms of energy output and that’s the mono-crystalline pane, which is the most popular in Ireland. At Caldor Solar we work with Sunpower, Jinko, Longi, Q-Cell, JA Solar, Canadian Solar & many other tier 1 brands. All the systems we use are recognised as being best in industry.
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